Combined endoscopic endonasal transpterygoid and sublabial transmaxillary approaches for a large infratemporal fossa trigeminal schwannoma

Acta Neurochirurgica (2022) 164:2525–2531

Trigeminal schwannomas (TSs) with solitary extracranial location are rare, and surgical excision is challenging. In recent years, the endoscopic endonasal transmaxillary transpterygoid approach (EETPA) has been advocated as an effective strategy for TSs in the infratemporal fossa (ITF).

Method We describe the steps of the EETPA combined with the sublabial transmaxillary approach for the surgical excision of a giant mandibular schwannoma of the ITF. Indications, advantages, and approach-specific complications are also discussed. The main surgical steps are shown in an operative video.

Conclusion A combined EETPA and sublabial transmaxillary approach represents a safe and effective option for the surgical excision of extracranial TSs.

Endoscopic Endonasal Transrotundum Middle Fossa Exposure: Technique of Transpterygoid Maxillary Nerve Transposition

World Neurosurg. (2018) 112:131-137

Middle fossa floor access can be challenging. Open skull base approaches have associated morbidity and yield suboptimal working angles around the temporal lobe. Endoscopic endonasal approaches to the middle fossa are poorly described, but provide an improved angle. I hypothesized that the length of the maxillary nerve can be transposed out of the foramen rotundum to provide a path to expose the full width of the middle fossa floor through the anterolateral and anteromedial triangle.

METHODS: Endoscopic endonasal transpterygoid dissections to expose the middle fossa were performed bilaterally on 2 silicone-injected cadaveric heads (4 sides). Transposition of V2 was then performed on all sides, and additional middle fossa exposure was achieved. Highresolution computed tomography imaging was obtained to quantify the extent of exposure. A transzygomatic approach was also performed for comparison.

RESULTS: The maxillary nerve was successfully transposed in each dissection. A periosteal fold was identified to assist in the mobilization of the infraorbital nerve. The average middle fossa exposure achieved without transposition was 50% (of the medial to lateral width). Transposition increased that to 95%. Comparison with the open transzygomatic approach demonstrated superior surgical trajectory (inferior to superior) with the endonasal route.

CONCLUSIONS: Endoscopic endonasal transpterygoid approaches with or without transposition of the maxillary nerve provide a reasonable option for sequentially exposing the entire medial to lateral extent of the anterolateral triangle. It provides an advantageous inferior to superior surgical angle and can be considered for treatment of select middle fossa floor pathology